OJ Board

Have WA, need help
Here is my code.
I don't know if not understood very well the problem

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

int main() {
string s;
bool prim = true;
int pez =0;
int cebo = 0;
int instr = 0;
int pez_cmp = 0;
getline(cin,s ...

#include <iostream>
#include <cmath>
using namespace std;

int main() {
cout.setf(ios::fixed);
cout.precision(3);
long n;
double a,tmp;
long b;
while(cin>>n) {
n=-n;
cout<<"2^"<<n<<" = ";
tmp=log10((double)2)*(n);
b=long(floor(tmp));
a=pow((double)10,tmp-b);
cout<<a<<'e'<<b<<endl;
}
}